Process for preparing a polyhydric alcohol ester of purified hydrogenated rosin



Patented Jan. -2,

UNITED STATES.

PROCESS FOR PREPARING A POLYHYDBIC .ALCOHOL ESTER F PURIFIED HYDRO- GENATED ROSIN Joseph N. Borglin, Wilmington, Del., assignor to Hercules Powder Company, Wilmington, Del., a corporation of Delaware No Drawing.

Application February 6, 1941,

. Serial No.3'l7,653

8 Claims. ((71. 260-100)- This invention relates to a process for preparin apolyhydric alcohol ester of purified hydrogenated rosin.

liberate the free hydrogenated rosin acids, extract this acidified mixture with a water-immiscible solvent for hydrogenated rosin such as a petro- In the copending application of J. M. Schantz, leum distillate such asgasoline, petroleum ether, Serial No. 3%,4'72, filed June 14, 1940, there is 5' etc., and evaporate the solvent from the extract described and claimed the use of a polyhydric alcohol ester of hydrogenated rosin in chewing gum. The manufacturer of chewing gum in accordance witth the teaching of that application is not altogether satisfactory because theresulting 1o chewing gum frequently displays an objectionable stickiness especiallyupon prolonged chewing. Moreover, the use of the polyhydric alcohol esters of hydrogenated rosin such as for example, the

glycerine ester, frequentlyimparts to the chewing 1o um a noticeable bitterness.

'It is an object of the present invention toprepare chewing gum embodying a polyhydric alcohol ester of hydrogenated resin which overcomes the disadvantages referred to above. object is to prepare a chewing gum embodying the glycerine ester of hydrogenated rosin and free from those disadvantages. to treat the resinous constituent of chewing gums of the typ referred to above so as to tree it from 28 any tendency to impart to the resulting chewing gum stickiness .or bitterness. Numerous other objects will more fully hereinafter appean I have discovered that the foregoing objects may be accomplished when the polyhydric alcohol ester of hydrogenated rosin such as the glycerine ester is freed from unesterifled' neutral bodies prior to its incorporation into the chewlng'gum material.

Another 20 Still another object is solution to recover the purified: hydrogenated rosin which is free from non-acid materials. The thus recovered'purified hydrogenated rosin. may then be esterified with the polyhydric alcohol such as glycerine and the resulting ester used im chewing gum.

Instead of the foregoing method of preparing the polyhydric. alcohol ester of hydrogenated rosin, I may extract the hydrogenated rosin acids. from ordinary hydrogenated rosin by the borax extraction method of the copending application of R. F. Cox, Serial NoT 381,779,filed March 5, 194i, whereby there .is obtained a hydrogenated rosin of high melting point and high freedom ifrom neutral bodies, and esterify the resulting resin with glycerine or th like to yielda resin which gives an improved chewing gum. Briefly the extracting the b'orax extract with ether and evaporating to recover the hydrogenated rosin acids.

\ Instead'of the foregoing extraction methods, I.

,may employ any other process which-yields a glycerine ester. of hydrogenated rosin having a meltingpoint above 90 C., an acid number below 3'5 and a content of unesteriiled neutral bodies less than 5%, such as by sparging the hydrogenated rosin or the glycerine ester thereof under reduced If the hydrogenated rosin from which the ester 36 pressure with steam,carb'on dioxide, or other gas is prepared is treatedso as to remove the neutral bodies therefrom prior to esteriflcation, the resulting' ester imparts no objectionable stickiness or bitterness to the chewing gum. To accomplish'this, the hydrogenated rosin may be treated. 40

by anextraction process so as to recover only the hydrogenated acidic bodies therein; Thus, I may dissolve the hydrogenated rosin in a water miscible or anic solvent such as-ethyl almixture with a water-immiscible organic solvent which is a solvent of all of the bodies initially present in the hydrogenated rosin and which therefore extracts the non-acid material therefrom. This solvent may be a petroleum distillate such as gasoline, petroleum ether, etc. ljthen acidifythe ramnate or extracted solution so as to 9 ated rosin which is at least 50% saturated. I

at high temperature for long periods of time, or distillation of the hydrogenated'rosin or the glycerine ester thereof under reduced pressure :until;

the content of unesteriilabl materials or unesterified neutral bodies-is reduced sufficiently" to give an'ester containing less than,5% and preferably 4, less than. 1% of unesterifiedneutral bodies. I prefer to treat both the hydrogenated rosin and the ester thereof by" this method. In general,

however,.the extraction procedures outlined above.

glycerine or the like and the ester treated by sparging or distillation under reduced pressure to remove any traces of unesterified neutral bodies or volatiles therein. I

I use the polyhydric alcohol ester of hydrogenmay esterify hydrogenated rosin the saturation figure of which varies from 50% to100% of the theoretical for two double bonds.

The glycerine ester of hydrogenated rosin employed in the formulation of the chewing gum in accordance with the present invention should have a melting point above 90C., an acid number not over about 35 and preferably not over about 10 and a content of unesterified neutral bodies less than about 5% and preferably less than about 1%. The use of a product oflow acid number is particularly desirable in order to avoid imparting any appreciable taste to the chewing gum.

' By following the principles outlined above, there isobtained an ester which has a melting softening agent should be present in limited point substantially above the melting point of the corresponding polyhydric alcohol ester of hydrogenated rosin produced by the conventional methods. Thus, the melting point of the by the Hercules drop-method.

While methods of formulating chewing gum embodying the resinous ester prepared as described above will be .obvious to those skilled in the art and will vary considerably depending upon the particular manufacture, for the sake of completeness it is deemed desirable to set forth below principles of formulating a chewing gum base therewith The polyhydric alcohol ester of hydrogenated rosin is preferably admixed with a rubber-like material such as gum chicle or substitutes there'- for, such as crepe rubbenrubber latex, guayule rubber, gutta percha, gutta sialr, jelutong,

pontianak, balata, factice, etc.- Natural rubber either as such or in the form of an aqueous dispersion such as rubber latex may be employed as the rubbery or rubber-like constituent of the chewing gum base. Synthetic rubber and latices made therewith may be used. It is preferred to use so-calledsynthetlc chicle, that is low grade natural vegetable rubber-like materials too high in resin content (resin content ranging from about 25% and usually from about40% to about 90%) to be useful for rubber, such, as materials selected from the group consisting of guttapercha, ielutong, balata, tuno, 'nama- .qualand rubber, almeidana gum abba rubber,

and inferior guttas such .asgutta siak, gutta cotie, gutta kay, 'gutta hangkang, gutta iangkar,

' resinousproduct is above 90 C. as determined amount, say not over of the chewing gum base so as to impart no objectionable oily characteristic to the chewing'gum.

It is frequently desirable to incorporate in the composition a wax or wax like material such as paraffln wax, beeswax, stearic acid,,candelilla wax, ceresin wax, etc. The amount of wax employed may vary up to about 25% of the chewing gum base. If desired, however, the wax content may be as high as say 50-75% byweight.

The. components *of thechewing gum base are intermixed, with one anothertin any manner which gives a homogeneous intimate mixture.

The rubbery material and the resinous ester may be admixed with each other by heating them together to a temperature at which they are fluent withstirring and maintenance of the temperature until a homogeneous mixture is obtained. If other components are employedsuch as resins other than the resinous ester of the present invention, a waxy material, or an oily softening agent, such other components may be commingled with the principal ingredients in thesame manner. It has been found to be particularly advantageous to effect the intermixture by working themixture on a roll mill at temperatures below the melting pointv of either the resinous or the rubbery ingredients, passing it throughthe rolls a number of times until the desired intermixture iseffected.

Where a waxy material and an oily softening agent are employed, admixture may be effected 4 by heating the oily soitening'material with the gum sundik, gutta soh', 'gutta susu, gutta f penang, yellow gutta and related materials and mixtures of the foregoingmaterlals with one another and with gum chicle. The polyhydric alcohol esters 'othydrogenatedrosin are com-- pletely miscible with the rubber-like materials named. Instead of using a single rubber-like material mixtures of two or more thereof may be employed. 1 Preferably, the rubbery component is employed-in an 'amount'such as to yield a ratio to the resinous ester ranging'from about 20 to 1 to about 1 to 10 and-preferably from about 2 to 1 to about 1 to 2.5. Equal parts by weight ofthe rubber-like material and the polyhydric alcohol-ester of hydrogenated rosin form a particularly desirable chewing gum base.

In addition to the rubbery material and the resinous ester, the chewing gum base may if desired, embodyother resins, synthetic or natural, such "as ordinary rosin, ordinary ester gum, cumarone resin, pontianak resin, copal gum.

kauri gum, damniar gum, sweet-bay'gum, spruce gum, balsams and the like. It is preferred to waxy material to an elevated temperature whereupon-the rubberymaterial and the resinous ester are stirred into the hot mixture until it is uniform.

Where a large proportion of waxy material is employed, it has been found to be advantageous to first mix the waxy material witlr;-the,;:eoolid rubber-like componentand heat toan; elevated temperature until the waxy component is molten, stirring and maintaining the temperature until a homogeneous mass is obtained whereupon the resinous, component and any other desired components are introduced into the mixture- It is frequently'desirable to incorporate small amounts of waterin the composition, this being particularly desirable where the rubbery or rubher-like material is in solid form.- The admin ture of water in this manner produces a mellowing and softening effect on [the gum. The amount of water incorporated in this manner may vary up to'say 10% of the chewing Bum base where the rubber like material is in solid mm;

Where an aqueous dispersion of the rubbery 7 component is employed there may be incor- -porated as much as 30% or 40% by weight of water in the composition. Similar large amounts bery component is solid.

, of water may, ifdesired, be used where the rub- I and ease of manufacture into the final gum which it imparts to the chewing gum base. I

- The hot chewing gum base prepared as desoftening and flavoring ingredients incorporated subsequently in any desired manner. Alternatively; the flavoring and sweetening'substituents may be added to the chewing gum base while it is still hot. There may be employed as sweetening agents the usual mixture of powdered sugar and glucose syrup or other agents such as invert sugar, levulose, saccharin, etc. As the flavoring constituents, there ma be employed the usual ingredients such as oil of peppermint, spearmint, wintergreen, etc., licorice, vanilla, vanillin, etc. Where gum chicle is not present in the mixture, dry cocoa powder or cocoa syrup maybe employed.

There may be incorporated in the mixture small amounts of a suitable flller material such as clay, calcium carbonate, magnesiumcarbonate, magnesium oxide, barium sulfate, calsium sulfate, carbon black, activated carbon, medicating agents such as phenolphthalein, mannitoi. etc.

As the polyhydric alcohol which is esterifled with the hydrogenated rosin, I prefer to employ those polyhydric alcohols having at least three carbon atoms and at least three hydroxyl groups and not more than six carbon atoms andnot more than sixhydroxyl groups such as glycerine,

. erythritol, pentaerythritol, xylitol. adonitol, arabitolisorbitol, 'mannitol, dulcitol, iditol, talitol, trimethylol methane, butantriol-l, 2, -3, pentaglycerol, rhamnitol, inner ethers of the hexa hydric alcohols such as mannitan, sorbitan, dulcitan, etc. Such esters are preferred because of their high meltingpoint-andthe non-toxic nature of the esters .and the alcohols. However.

other polyhydric alcohol esters may be used such as the glycol esters although on account of the softness of the glycol esters and the reported toxicity of certain of the 'glycols, such esters are not preferred. I may use esters of still higher polyhydric alcohols such as perseitol. Iactositol, volemnitol, enneaheptite, etc. I may "use esters with other non-toxic saturated aliphatic compounds having a plurality of hydroxy groups such as glucose, sucrose, the dihydroxylinner ether derivatives of the hexahydric alcohols such as mannide, sorbide, dulcide, etc., non-'toxic-polyhydroxy carboxylic acids such as glyceric acid,

'gluconic acid, tartaric acid, trihydro'xy glutaric' acid. tetrahydroxy adipic acid, mucic acid, saccharic acid, etc.- a

Following are examples showing the preparation of a highly purified ester by highly purifying the hydrogenated rosin prior to esteriflcaq vantageous because of the desirableconsistency scribed above may be allowed tocool and the to remove excess glycerine.

tion w... then acidifled was 2300 g. of log. H2804. The acidified solution was extracted with 6 lots of 1 liter of petroleum ether. The

1 petroleum ether extract was washed with water and all volatiles distilled off. The resinous residue consisted of the purified hydrogenated Ipsin acids. This resinous residue was esterifled by heating with'18%% of its weight of glycerine for 18 hours at 270-280 C. with a hot water re-, flux condenser. When the acid number reached 4, the mixture wassparged with CO: for 9* hours The rate of esterification was considerably decreased by the removal of the non-acid materials from the hydrogenated resin." The resulting ester had a color of amber, an acid number of 3.8, a drop melting point of 91 C. and a volatile oil content Example 2 Two hundred and fifty parts by weight of the sameliydrogenated rosin as was used in Example 1 was dissolved in 700 parts by weight or ethyl' ether, and extractedwith 1000 parts of 5% .aque-' cedure was repeated twenty threetimes. The

, hydrogenate dresin acids were isolated by evaporation of the ether extract and analyzed; drop melting point 83.7" 0., acid number 174.0, saponiflcation number 176.7 and thiocyanogen number 28.0. This hydrogenated rosin was esterified with glycerine in exactly the same manner as in Example 1. The resulting ester had a color of 26 amber, an acid number of 2.0, and a drop melting point of 96 C.

Example 3 Five hundred parts by weight of the same hydrogenated rosin as was used in Examples 1 and 2 was maintained at a temperature of 100- 120 C. and sparged with steam, which had been passed through a gas fired superheater. The

steam was at a temperature of about 180 C. This treatment was continued for one hour. The

' product had a melting point of 80-81 C., an acid number of 164;- and a color of 10 amber. product was mixed with 13% of its weight of glycerine and the mixture heated for 18 hours at 270-280 C. The ester was then sparged with a steam at 280-290 C. for two hours.

The resulting ester had an acid number of 3, a melting point of 90.5 C. and a color of 30 amber.

Below are given specific examples showing the formulation of chewing gum bases in accordance I with the present invention.

tion. In Example 3, the ester was also purified.

.Fifteen hundred g. of hydrogenated rosin (sat, uration acid number 161, drop melting point. 79 C. and colorof 5 amber or an X grade) were dissolved in 6 liters of' denatured ethyl alcohol (formula 23). .To this solution there was added withstirring 188 g. of NaOH in 61iters of water (somewhat more than sufficient to effect complete neutralization). The neutralized mixture was extracted Btimes with 1 liter of petroleum ether perextraction. The extracted soluseed oil were'melted together and heated to 'C. whereupon the rubber was slowly added in small portions with stirring and the temperature.

of the mixture radually raised to C. The

S m. 21 316 was added and themixture stirred The ' undesirable flavors and until uniform. Then the resin was added, the mixture again stirred until uniform and poured into a mold to cool. There was obtained a plastic mass which was highly resistant to deterioration upon ageing and which when sweetened and flavored yielded a chewing gum having very desirable chewing gum .characteristics and good re- The paraflin was melted and the rubber was then added. This mixture was slowly heated to 135 C. at which temperature the mix became uniform. Then the temperature was slowly raised to 145-150" C. whereupon the resins and the beeswaxwere added, the mixture stirred until uniform and allowed to cool. When the temperature ,had dropped to 95-100" C., the water was stirred'in and the mixture poured into a mold and allowed to cool. A light colored material free of with good chewing qualities was obtained.

Example 6 V g Parts by weight Rubber latex (40% rubber) 40 Water 40 Purified glycerine ester of purified hydrogenated rosin (product of Example 3) 40 Stearic acid 25 Hydrogenated cottonseed oil (Crisco") 25. Cocoa powder '1 The materials were'mixed thoroughly at room temperature, and then heated slowly at 100-115- C. with stirring and maintenance at this temperature until all of the water and latex preservative (ammonia and formaldehyde) had been driven off. The time required was about one hour. The hot mixture was then poured into a. mold and allowed to cool. The chewing gum obtained exhibited a rubbery characteristic similar to gum chicle, but was freeof undesirable flavors.

amples hereinbefore set forth are illustrative only and that the invention as broadly described and claimed is in no wav limited therebw. i

What I claim and desire to protect by Letters Patent is:

1. The process of preparing a giycerine ester of hydrogenated rosin comprising dissolving hydrogenated rosin in a water-miscible organic solvent, neutralizing the solution with an aqueous solution of an alkali, extracting the neutralized mixture with a water-immiscible organic solvent, acidifying the extracted solution, extracting the acidified mixture with a water-immiscible organic solvent for hydrogenated rosin, evaporating the solvent from the extract to recover the purified hydrogenated rosin, and esterifying the recovered .purified hydrogenated rosin with glycerine to' form an ester having an acid number of not over about 10. z

It will be understood that the details and exvent from the extract to recover hydrogenatedrosin acids, and esterifying the recovered -hydrogenated rosin acids with a polyhydric alcoholv having at least three carbon atoms and at least three hydroxyl groups and not more than six carbon atoms and not more than six hydroxyl groups to form an ester having an acid number of not over about 10.

3. A process as set forth in claim 2 in which the ester is treated by sparging under reduced.

pressure, thereby removing traces of unesterified neutral bodies or volatiles therefrom.

4. A process as set forth in claim .2 in which the ester is subjected to distillation under reduced pressure thereby removing traces of unesterified neutral bodies or volatiles therefrom.

5. The process of preparing a pentaerythritol ester of hydrogenated rosin of reduced stickiness, improved taste, and increased melting point which comprises dissolving hydrogenated rosin in a water-miscible organic solvent, neutralizing the solution with an aqueous solution of an alkali, extracting the neutralized mixture with a petroleum distillate solvent, acidifying the extracted solution, extracting the acidified mixture with a petroleum distillate solvent, evaporating the solvent from the extract to recover hydrogenated rosin acid, and esterifying the recovered hydrogenated rosin'acids with pentaerythritol to form an ester having an acid number of not over aboutlO.

6. The process of preparing a polyhydric alcohol ester of hydrogenated rosin of reduced stickiness, improved taste, and increased melting point, which comprises dissolving hydrogenated rosin in ethyl alcohol, neutralizing the solution with an aqueous solution of an alkali, ex- ,tracting the neutralized mixture with a petroleum distillate solvent, acidifying the extracted solution, extracting the .acidified mixture with a petroleum distillate solvent, evaporating the solvent-from the extract to recover hydrogenated rosin acids, and esterify ing the recovered hydrogenated rosin acids with a polyhydric alcohol to form an ester having an acid-number of not over about 10. i

7. The process of preparing a polyhydric alcohol ester of hydrogenated rosin of reduced stickiness, improved taste, and increased melting point, which comprises dissolving hydrogenated rosin in acetone, neutralizing the solution with an aqueous solution of an alkali, extracting the neutralized mixture with a gasoline solvent, acidifying the extracted solution, extracting the acidified mixture with gasoline, evaporating the solvent. from the extract to recover hydrogenated rosin acids, and esterifying the recovered hydrogenated rosin acids with a polyhydric alcohol thereby forming an ester having anacid number of not over about 10. 1

8. In a process for the preparation of a polyhydric alcohol resinous ester of minimum taste, decreasedstickiness, and increased melting point, in comparison with a similar ester of hydrogening the'neutralizedxmlxture with a water-immiscibleorganic/solvent, acidifying the exitracted solution, extracting the acidified mixture with a water-immiscible organic solvent for hydrogen- *ated rosin, and-evaporating the solvent from the extract to recover hydrogenated rosin acids.

JOSE H N. BORGLIN. 

